Fatal Acute Hemolytic Transfusion Reaction (AHTR), ABO mistyping

Ready to upload
Record number: 
Adverse Occurrence type: 
MPHO Type: 
Estimated frequency: 
Case report
Alerting signals, symptoms, evidence of occurrence: 
The patient's temperature, blood pressure, and pulse rate increased after fourth incompatible RBC unit given; chills, cyanosis, hemoglobinuria and hemoglobinemia were also noted. During the serologic investigation, the reference laboratory found that the patient was group A, not AB. The mistyping was found to be due to the presence of an acquired B antigen on the patient's RBCs and the use of a monoclonal anti-B (Gamma Biologicals Inc., Houston, TX) that reacted strongly with such RBCs.
Demonstration of imputability or root cause: 
Serologic testing and an explanation for missing weak anti-B antibodies during the initial pre-transfusion compatibility testing.
Imputability grade: 
3 Definite/Certain/Proven
Groups audience: 
Suggest new keywords: 
acquired B antigen
acute hemolytic reaction, monoclonal typing reagents
Reference attachment: 
Suggest references: 
Garratty G, Arndt P, Co A, Rodberg K and Furmanski M. (1996). Fatal hemolytic transfusion reaction resulting from ABO mistyping of a patient with acquired B antigen detectable only by some monoclonal anti-B reagents. Transfusion 36:351-7
Expert comments for publication: 
This case is of historic interest. At the time the report appeared there was concern that immunohematologists needed to be aware of idiosyncracies of monoclonal immunohematology reagents. The reagent manufacturer reduced the pH of the monoclonal typing reagent such that it detected only strong acquired B antigens. This lead to false-positive reactions when unwashed RBC's from patients with pH-dependent cold autoagglutins (e.g. anti-Pr) were tested.